Birds' eggs are commonly regarded as a food source by non-vegans. The most-used eggs are chicken, duck and goose, but smaller eggs such as quail eggs are occasionally used as a gourmet ingredient. Eggs are frequently used in both sweet and savoury dishes as a source of protein and/or to bind the other ingredients in a recipe together. Egg-yolks contain a small amount of fat and cholesterol, and people on a low-cholesterol diet may feel the need to cut down on egg consumption, though scientists are unsure of the merit of such a move. Egg-whites consist primarily of water (7/8th) and protein (1/8th) and contain no cholesterol or fat.